1. Field of the Invention
This invention relates to a plastic material containing a microbicidally effective amount of calcium pyroborate and a process for protecting a plastic material from microbiological attack.
2. Description of the Related Art
Microbiological fouling of plastic materials is an unwanted nuisance and a problem in many household and industrial environments. The humid and high moisture environments where plastic materials are often used provide excellent growth environments for unwanted microorganisms such as mold, fungi, and mildew. In addition to degrading and fouling plastic materials, these microorganisms can cause unsightly stains and unpleasant odors.
The plastics industry has used various microbicides to prevent the growth of microorganisms on plastic materials. U.S. Pat. Nos. 4,086,297 and 5,270,108 provide a discussion of the use of microbicides with plastics. Barium metaborate is an example of a microbicide used in a wide variety of plastics. OBPA, Oxy-Bis-Phenoxy-Arsine, the most commercially significant microbicide, is found in a wide range of plastic consumer goods such as waterbed mattresses and shower curtains.
As environmental concern has increasingly focused on contaminants introduced into groundwater, regulatory scrutiny has also focused on the disposal of many materials and products including plastics. Regulatory authorities have discouraged or even regulated the use of acute human toxicants and carcinogenic materials. Thus, the plastics industry has been looking for environmentally favorable biocides.
The plastics industry places strict physical requirements on microbicides for use in plastic materials. The microbicide should be temperature and pressure stable. It should have limited solubility in water to perform as a long term microbicide of a plastic article. For exterior applications where the plastic material is exposed to the environment, the microbicide should also have significant ultraviolet radiation stability. Thus, there remains a need for an effective biocide which is useful with plastic materials and articles and meets the strict requirements of the plastics industry.